Near-Infrared Electrochemiluminescence from Bistridentate Ruthenium(II) Di(quinoline-8-yl)pyridine Complexes in Aqueous Media.

We report the synthesis, photophysics, electrochemistry and electrochemiluminescence (ECL) of two dqp (dqp=2,6-di(quinoline-8-yl)pyridine) based ruthenium(II) complexes, bearing either a n-butyl ester (1) or the corresponding carboxylic acid functionality (2). The complexes were prepared from [Ru(dqp)(MeCN) ][PF ] by reaction with the dqp precursor using microwave irradiation. In both cases, photoluminescence spectra present strong MLCT-based red/near-infrared (NIR) emissions centred at about 710 nm.

Interactions between an amphipathic di-histidine peptide and a metal affinity chromatographic resin derived from a bis(tacn)butane chelating ligand.

The interactive behavior of an amphipathic peptide with the Cu , Ni , and Zn complexes of 1,4-bis(triazacyclonon-1-yl)butane), bis(tacn) , immobilized onto Sepharose CL-4B, has been investigated. The effects of incubation time, as well as the incubation buffer pH and ionic strength, have been examined. The binding data have been interrogated using Langmuir, Langmuir-Freundlich, bi-Langmuir, and Temkin isothermal models and Scatchard plots.

Molecular Engineering of Zinc-Porphyrin Sensitisers for p-Type Dye-Sensitised Solar Cells.

Invited for this month's cover are the groups of Prof. Dr. Udo Bach, Prof.

Transformation of Indium and Gallium Metal into Mixed Group 11/13 Ternary Sulfide Nanoparticles by Using a Dithioic Acid.

Heterobimetallic Group 11/13 sulfide nanoparticles (AgInS , CuInS , Ag GaS , and CuGaS ) are formed by treatment of [M(S CAr) ] (M=Ga or In) with either AgNO or CuCl under mild conditions. The intermediary gallium or indium tris(aryldithioate) complexes are easily prepared by stirring the appropriate metal and aryldithioc acid at room temperature. Overall, this two-step process is a simple solution-based method for transforming Ga and In metal into valuable ternary metallosulfide nanoparticles at relatively low temperatures.

Molecular Engineering of Zinc-Porphyrin Sensitisers for p-Type Dye-Sensitised Solar Cells.

Design of novel efficient light-harvesters for p-type dye-sensitised solar cells (DSSCs) is indispensable for further advances in this photovoltaic technology. Herein, a novel D-π-A (D=donor, π=π-conjugated linker, A=acceptor) sensitiser, ZnP1, featuring an electron acceptor, perylenemonoimide (PMI), connected to an electron donor, di(p-carboxyphenyl)amine (DCPA), through fluorene and a zinc(II) porphyrin with alkyl chains as a π-conjugated bridge is introduced. Spectroscopic and electrochemical characterisation of this dye along with a newly synthesised PMI-free reference dye ZnP0 has been undertaken to demonstrate strong electron coupling between the DCPA donor and PMI acceptor subunits through the porphyrin ring in ZnP1, which redshifts the light absorption onset to the near-IR region.

Macrocycles Bearing Ferrocenyl Pendants and their Electrochemical Properties upon Binding to Divalent Transition Metal Cations.

Metal complexes of Cu , Co , Cd , Zn , and Ni formed with the ligands [Fc(cyclen)] (1) and [Fc(cyclen) ] (2) (Fc=ferrocene, cyclen=1,4,7,10-tetraazacyclododecane) are synthesised and characterised. The X-ray structure of the Cu complex of 2, Fc([Cu(cyclen)(CH CN)] (ClO ) , is reported, and shows that the two positively charged Cu -cyclen units have a coordination number of five, adopting a distorted trigonal-bipyramidal configuration. The Cu -cyclen units are arranged in a trans-like configuration with respect to the Fc group, presumably to minimise electrostatic repulsion.

Electrolysis of Natural Waters Contaminated with Transition-Metal Ions: Identification of A Metastable FePb-Based Oxygen-Evolution Catalyst Operating in Weakly Acidic Solutions.

The possibility of efficient water electrooxidation sustained by continuous (re)generation of catalysts derived from the oxidative electrodeposition of transition-metal contaminants is examined herein for three natural water samples from Australia and China. The metal composition of the solutions has been determined by inductively coupled plasma optical emission spectrometry, and a range of strategies to produce water-splitting catalysts by means of in situ electrodeposition have been applied. The performance of the resulting electrocatalysts is below the state-of-the-art level owing to large amounts of impurities in the solutions and non-optimal concentrations of naturally available catalyst precursors.

Spectroscopic Studies on Photoinduced Reactions of the Anticancer Prodrug, trans,trans,trans-[Pt(N ) (OH) (py) ].

The photodecomposition mechanism of trans,trans,trans-[Pt(N ) (OH) (py) ] (1, py=pyridine), an anticancer prodrug candidate, was probed using complementary Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR), transient electronic absorption, and UV/Vis spectroscopy. Data fitting using Principal Component Analysis (PCA) and Multi-Curve Resolution Alternating Least Squares, suggests the formation of a trans-[Pt(N )(py) (OH/H O)] intermediate and trans-[Pt(py) (OH/H O) ] as the final product upon 420 nm irradiation of 1 in water. Rapid disappearance of the hydroxido ligand stretching vibration upon irradiation is correlated with a -10 cm shift to the antisymmetric azido vibration, suggesting a possible second intermediate.

Dipole-field-assisted charge extraction in metal-perovskite-metal back-contact solar cells.

Hybrid organic-inorganic halide perovskites are low-cost solution-processable solar cell materials with photovoltaic properties that rival those of crystalline silicon. The perovskite films are typically sandwiched between thin layers of hole and electron transport materials, which efficiently extract photogenerated charges. This affords high-energy conversion efficiencies but results in significant performance and fabrication challenges.

Tunable Biogenic Manganese Oxides.

Influence of the conditions for aerobic oxidation of Mn2+(aq) catalysed by the MnxEFG protein complex on the morphology, structure and reactivity of the resulting biogenic manganese oxides (MnO ) is explored. Physical characterisation of MnO includes scanning and transmission electron microscopy, and X-ray photoelectron and K-edge Mn, Fe X-ray absorption spectroscopy. This characterisation reveals that the MnO materials share the structural features of birnessite, yet differ in the degree of structural disorder.

Controlled Growth of Monocrystalline Organo-Lead Halide Perovskite and Its Application in Photonic Devices.

Organo-lead halide perovskites (OHPs) have recently emerged as a new class of exceptional optoelectronic materials, which may find use in many applications, including solar cells, light emitting diodes, and photodetectors. More complex applications, such as lasers and electro-optic modulators, require the use of monocrystalline perovskite materials to reach their ultimate performance levels. Conventional methods for forming single crystals of OHPs like methylammonium lead bromide (MAPbBr ) afford limited control over the product morphology, rendering the assembly of defined microcavity nanostructures difficult.

Formation of Group 11 Bismuth Sulfide Nanoparticles Using Bismuth Dithioates under Mild Conditions.

The formation of mixed-metal sulfides with the general structure AgBiS and Cu BiS by a simple two-step process utilizing bismuth dithiocarboxylates as Bi and S precursors is described. A sonochemical reaction of Bi O with six different aryl dithioic acids: dithiobenzoic acid (BDT-H), 4-methoxydithiobenzoic acid (4-MBDT-H), 3-methyldithiobenzoic acid (3-MBDT-H), 2-mesitylenedithioic acid (2-MDT-H), 4-fluorodithiobenzoic acid (4-FBDT-H), and 2-thiophenedithioic acid (2-TDT-H) resulted in the corresponding complexes: [Bi(BDT) ] 1, [Bi(4-MBDT) ] 2, [{Bi(3-MBDT) } ⋅C H ] (3 ⋅C H ), [Bi(2-MDT) ] 4, [Bi(4-FBDT) ] 5 and [Bi(2-TDT) ] 6. Microwave irradiation of these bismuth(III)aryldithioate complexes with AgNO or CuCl under mild reaction conditions (140 °C) resulted in the respective mixed-metal sulfides.

Studies of Carbon Monoxide Release from Ruthenium(II) Bipyridine Carbonyl Complexes upon UV-Light Exposure.

The UV-light-induced CO release characteristics of a series of ruthenium(II) carbonyl complexes of the form trans-Cl[RuLCl(CO)] (L = 4,4'-dimethyl-2,2'-bipyridine, 4'-methyl-2,2'-bipyridine-4-carboxylic acid, or 2,2'-bipyridine-4,4'-dicarboxylic acid) have been elucidated using a combination of UV-vis absorbance and Fourier transform infrared spectroscopies, multivariate curve resolution alternating least-squares analysis, and density functional theory calculations. In acetonitrile, photolysis appears to proceed via a serial three-step mechanism involving the sequential formation of [RuL(CO)(CHCN)Cl], [RuL(CHCN)Cl], and [RuL(CHCN)Cl]. Release of the first CO molecule occurs quickly (k ≫ 3 min), while release of the second CO molecule proceeds at a much more modest rate (k = 0.

Effects of guanidino modified aminoglycosides on mammalian membranes studied using a quartz crystal microbalance.

The increase in bacterial and viral resistance to current therapeutics has led to intensive research for new antibacterial and antiviral agents. Among these, aminoglycosides and their guanidino derivatives are potent candidates targeting specific RNA sequences. It is necessary that these substances can pass across mammalian membranes in order to reach their intracellular targets.

Zwitterionic Modification of Ultrasmall Iron Oxide Nanoparticles for Reduced Protein Corona Formation.

Polyacrylic-acid-coated ultra-small super-paramagnetic iron oxide nanoparticles were surface-modified with low-molecular-weight sulfobetaines or 3-(diethylamino)propylamine in order to generate nanoparticles with zwitterionic character (ZW-NPs). The ZW-NPs proved highly resistant to serum protein corona formation in vitro, as revealed by atomic force microscopy, SDS-PAGE and proteomics analysis, and exhibited low cytotoxicity towards A431 and HEK293 cells. The presence of unreacted carboxylic acid groups enabled additional functionalization with fluorescent (Cy5) and radioactive [ Cu-dmptacn; dmptacn=1,4-bis(2-pyridinylmethyl)-1,4,7-triazacyclononane] moieties.

Direct observation of intrinsic twin domains in tetragonal CHNHPbI.

Organic-inorganic hybrid perovskites are exciting candidates for next-generation solar cells, with CHNHPbI being one of the most widely studied. While there have been intense efforts to fabricate and optimize photovoltaic devices using CHNHPbI, critical questions remain regarding the crystal structure that governs its unique properties of the hybrid perovskite material. Here we report unambiguous evidence for crystallographic twin domains in tetragonal CHNHPbI, observed using low-dose transmission electron microscopy and selected area electron diffraction.

Parameterization of Water Electrooxidation Catalyzed by Metal Oxides Using Fourier Transformed Alternating Current Voltammetry.

Detection and quantification of redox transformations involved in water oxidation electrocatalysis is often not possible using conventional techniques. Herein, use of large amplitude Fourier transformed ac voltammetry and comprehensive analysis of the higher harmonics has enabled us to access the redox processes responsible for catalysis. An examination of the voltammetric data for water oxidation in borate buffered solutions (pH 9.

Biogenic Manganese-Oxide Mineralization is Enhanced by an Oxidative Priming Mechanism for the Multi-Copper Oxidase, MnxEFG.

In a natural geochemical cycle, manganese-oxide minerals (MnO ) are principally formed through a microbial process, where a putative multicopper oxidase MnxG plays an essential role. Recent success in isolating the approximately 230 kDa, enzymatically active MnxEFG protein complex, has advanced our understanding of biogenic MnO mineralization. Here, the kinetics of MnO formation catalyzed by MnxEFG are examined using a quartz crystal microbalance (QCM), and the first electrochemical characterization of the MnxEFG complex is reported using Fourier transformed alternating current voltammetry.

Towards a Bioinspired-Systems Approach for Solar Fuel Devices.

What lies ahead? In the development of solar fuel devices Nature provides the blueprint for artificial photosynthesis and water oxidation/reduction catalysts. Researchers have come a long way, but many challenges lie ahead.

Catalytic Systems for Water Splitting.

Power source: The water-splitting reaction is the most important reaction for the conversion of solar energy to fuel. In this special issue our Guest Editors have gathered contributions highlighting recent advances in the field. Pictured is a Yangtze River waterfall.

Solar Water Oxidation by Multicomponent TaON Photoanodes Functionalized with Nickel Oxide.

Efficient solar-powered water oxidation over the TaON-based anodes requires coupling this photoactive n-type semiconductor to an electrooxidation catalyst to improve the otherwise unsatisfactory activity and stability. Herein, we examine how functionalization with electrodeposited nickel oxide, NiO , affects the performance of screen-printed TaON photoanodes post-necked with titania (TiO -TaON). The effects of the NiO photo-electrodeposition parameters on the microstructure and photocatalytic performance of the resulting anodes are explored.

Comprehensive Vibrational Spectroscopic Investigation of trans,trans,trans-[Pt(N3)2(OH)2(py)2], a Pt(IV) Diazido Anticancer Prodrug Candidate.

We report a detailed study of a promising photoactivatable metal-based anticancer prodrug candidate, trans,trans,trans-[Pt(N3)2(OH)2(py)2] (C1; py = pyridine), using vibrational spectroscopic techniques. Attenuated total reflection Fourier transform infrared (ATR-FTIR), Raman, and synchrotron radiation far-IR (SR-FIR) spectroscopies were applied to obtain highly resolved ligand and Pt-ligand vibrations for C1 and its precursors (trans-[Pt(N3)2(py)2] (C2) and trans-[PtCl2(py)2] (C3)). Distinct IR- and Raman-active vibrational modes were assigned with the aid of density functional theory calculations, and trends in the frequency shifts as a function of changing Pt coordination environment were determined and detailed for the first time.

Charge Transfer Dynamics at Dye-Sensitized ZnO and TiO2 Interfaces Studied by Ultrafast XUV Photoelectron Spectroscopy.

Interfacial charge transfer from photoexcited ruthenium-based N3 dye molecules into ZnO thin films received controversial interpretations. To identify the physical origin for the delayed electron transfer in ZnO compared to TiO2, we probe directly the electronic structure at both dye-semiconductor interfaces by applying ultrafast XUV photoemission spectroscopy. In the range of pump-probe time delays between 0.

Cellular Uptake and Photo-Cytotoxicity of a Gadolinium(III)-DOTA-Naphthalimide Complex "Clicked" to a Lipidated Tat Peptide.

A new bifunctional macrocyclic chelator featuring a conjugatable alkynyl-naphthalimide fluorophore pendant group has been prepared and its Gd(III) complex coupled to a cell-penetrating lipidated azido-Tat peptide derivative using Cu(I)-catalysed "click" chemistry. The resulting fluorescent conjugate is able to enter CAL-33 tongue squamous carcinoma cells, as revealed by confocal microscopy, producing a very modest anti-proliferative effect (IC50 = 93 µM). Due to the photo-reactivity of the naphthalimide moiety, however, the conjugate's cytotoxicity is significantly enhanced (IC50 = 16 µM) upon brief low-power UV-A irradiation.